Objective:To screen the factors influencing overall survival (OS) of patients undergoing radical resection for colorectal cancer (CRC) and to construct a prognostic model for OS of patients after CRC.Methods:The clinical data of 350 patients with stage Ⅰ-Ⅳ CRC who underwent radical resection in the People's Hospital of Wuhan University from March 2017 to December 2019 were collected retrospectively. Patients were divided into subgroups 0 ( n=70), 1 ( n=172), and 2 ( n=108) according to different preoperative systemic inflammation score (SIS). The relationship between different SIS, neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), systemic immune inflammation index (SII) and prognosis of CRC patients undergoing radical surgical resection were analyzed, and Cox regression models were used to perform univariate and multifactorial analyses of factors affecting patient prognosis, and column line graph models were constructed based on the results of multifactorial analyses. Results:By the deadline of follow-up, 80 of 350 CRC patients died, and the 5-year OS rate was 77.14%. The 5-year survival rates of patients in SIS group 0, group 1 and group 2 were 95.71%, 79.65% and 61.11% respectively, with a statistically significant difference ( χ2=30.19, P<0.001). Statistically significant differences in age ( χ2=19.40, P<0.001), tumor site ( χ2=8.18, P=0.017), T stage ( χ2=10.01, P=0.007), TNM stage ( χ2=14.80, P=0.001), tumor diameter ( χ2=13.91, P=0.001) and carcino-embryonic antigen (CEA) level ( χ2=10.12, P=0.006) among patients in SIS group 0, group 1 and group 2. The 5-year OS rates of patients in the low NLR and high NLR groups were 82.67% and 56.16% respectively, with a statistically significant difference ( χ2=24.96, P<0.001) ; the 5-year OS rates of patients in the low LMR and high LMR groups were 66.85% and 88.17% respectively, with a statistically significant difference ( χ2=22.45, P<0.001) ; the 5-year OS rates of patients in the low SII and high SII groups were 86.14% and 69.02% respectively, with a statistically significant difference ( χ2=14.76, P<0.001). Univariate analysis showed that age ( HR=2.58, 95% CI: 1.54-4.32, P<0.001), T stage ( HR=2.41, 95% CI: 1.24-4.68, P=0.009), N stage ( HR=3.03, 95% CI: 1.85-4.94, P<0.001), TNM stage ( HR=3.61, 95% CI: 2.15-6.04, P<0.001), nerve invasion ( HR=1.97, 95% CI: 1.27-3.08, P=0.002), vascular invasion ( HR=2.31, 95% CI: 1.49-3.59, P<0.001), preoperative SIS 1 score ( HR=5.09, 95% CI: 1.57-16.56, P=0.007), SIS 2 score ( HR=11.05, 95% CI: 3.42-35.65, P<0.001), NLR ( HR=2.97, 95% CI: 1.90-4.64, P<0.001), LMR ( HR=0.31, 95% CI: 0.19-0.52, P<0.001), and SII ( HR=2.50, 95% CI: 1.54-4.06, P<0.001) were all independent influence factors affecting the postoperative prognosis of CRC patients undergoing radical surgical resection; multivariate analysis showed that age >60 years ( HR=2.27, 95% CI: 1.31-3.91, P=0.003), TNM stage Ⅲ-Ⅳ ( HR=7.08, 95% CI: 1.89-26.59, P=0.004), and preoperative SIS 2 score ( HR=4.02, 95% CI: 1.09-14.83, P=0.037) were all independent risk factors affecting the postoperative prognosis of CRC patients undergoing radical surgical resection. The nomogram model built based on the screened variables has high prediction accuracy: the C-index of the nomogram was 0.75. Conclusion:Age>60 years old, TNM stage Ⅲ-Ⅳ, SIS 2 score are all independent risk factors for postoperative prognosis of colorectal cancer. The nomograph model constructed by this method has high prediction accuracy.